Arching mechanism

Abstract

Arching mechanism, for instance for backrests of seats, medical or orthopaedic apparatus or casings and the like, with a pressure element wherein at least one traction element connected with a tensioning mechanism engages, which, when the mechanism is actuated can produce bulging by preserving a relative elevation of apex of the convexity; the arching mechanism can comprise a frame with inserted pressure elements actuatable by adjusting device(s), whereby frame segments are length-variable pressure elements; traction elements provided with tensioning mechanism can engage a slitted, overlapping or bellows-like bulging body for the opening and closing of these areas, which produces a curving of the bulging body in a predetermined direction or directions.

What is claimed is:  
     
       1. A lumbar support for a back of a seat, comprising: 
       a flexible structure including first and second end portions; and  
       a traction device comprising:  
       a bowden cable having a wire anchored to one of said end portions and a sleeve anchored to said lumbar support and through which said wire is guided; and  
       a mechanism connected to said wire for tensioning said wire to draw one of said first and second end portions toward the other of said first and second end portions thereby controllably arching said flexible structure.  
     
     
       2. A lumbar support for a back of a seat, comprising: 
       an upper section and a lower section spaced below said upper section;  
       a flexible structure connecting said upper and lower sections and adapted to bow upon displacement of at least one of said sections toward the other, thereby forming a curvature in said flexible structure; and  
       a bowden cable having a wire anchored to said lower section and a sleeve anchored to the upper section of said lumbar support and through which said wire is guided; and  
       a mechanism connected to said wire for tensioning said wire to draw one of said upper section and said lower section toward the other of said upper section and said lower section, thereby controllably arching said flexible structure.  
     
     
       3. A lumbar support for a back of a seat, comprising: 
       an upper section and a lower section spaced below said upper section;  
       a flexible vertical structure connecting said upper and lower sections and adapted to bow upon displacement of at least one of said sections toward the other thereby forming a curvature in said flexible vertical structure; and  
       a bowden cable having a wire anchored to an upper portion of said lumbar support and a sleeve anchored to a lower portion of said lumbar support and through which said wire is guided; and  
       a mechanism connected to said wire for tensioning said wire to draw one of said upper portion of said lumbar support and said lower portion of said lumbar support toward the other of said upper portion of said lumbar support and said lower portion of said lumbar support, thereby controllably arching said flexible vertical structure.  
     
     
       4. A lumbar support for a back of a seat, comprising: 
       a flexible structure including opposite end portions;  
       a bowden cable having a wire anchored to one of said end portions and a sleeve anchored to the other of said end portions and through which said wire is guided;  
       a spring operatively connecting one of said end portions to said wire or said sleeve; and 
       a mechanism connected to said wire for tensioning said wire to draw one of said end portions toward the other of said end portions to selectively increase an arch of said flexible structure.  
     
     
       5. A lumbar support for a back of a seat, comprising: 
       a flexible structure including a first end and a second end;  
       a bowden cable having a wire and a sleeve through which said wire is guided, said wire anchored to said flexible structure, a spring operatively connecting said sleeve to said flexible structure; and  
       a mechanism connected to said wire for tensioning said wire to draw said first end toward said second end to selectively arch said flexible structure.  
     
     
       6. The lumbar support of claim  5  further including a spring operatively connecting said flexible structure to at least one of said wire or said sleeve. 
     
     
       7. A lumbar support for a back of a seat, comprising: 
       an upper member and a lower member spaced below said upper member;  
       a flexible structure including first and second end portions; and  
       a traction device comprising:  
       a bowden cable having a wire anchored to one of said end portions and a sleeve anchored to said lumbar support and through which said wire is guided; and  
       a mechanism connected to said wire for tensioning said wire to draw one of said first and second end portions toward the other of said first and second end portions thereby increasing an arch of said flexible structure.  
     
     
       8. The lumbar support of claim  7  further including a spring operatively connecting said flexible structure to said sleeve.